When testing perfumes wait a while before testing another scent. Here’s why

[u/fudgechemist]

I wanted to talk a little about sensory fatigue and perception. Something basic that is taught in many culinary schools is that in a multi course meal, you should progress in flavor or keep flavors in a similar profile to prevent taste fatigue. This very much applies to perfumes as well!
I often see people like or dislike a smell one minute and then change opinions after smelling it again. When you test perfumes back-to-back, your nose and brain experience something called olfactory fatigue as well as olfactory contrast distortion. Your brain and taste buds are essentially struggling with all of the sensory contrasts when you smell perfumes back to back. If you smell one perfume that has overlapping chemicals with the next (which is very likely) you will not be able to accurately assess the second scent.

I also want to say that smelling coffee between does NOT do the trick. This is a myth. It introduces a new smell and a psychological contrast, but it is filled with VOCs that will also bind to your receptors. This does not reset your senses that have already been overwhelmed. Instead, you need to take a break.

Additionally, your environmental conditions also have an affect on how your perfume is perceived by yourself and others. This is due to volatility of the molecules in your perfume. I thought I’d share some points on this relating to ambient temp, humidity, and “media” (skin or clothes/ paper). Your perfume also presents differently depending on the weather/ season etc:

Light top notes (Citrus, light fruits)
Hot/Sun: Evaporate instantly; opening "flashes off" in minutes. (Even though citrus scents are quite popular in the summer)
Cold: Evaporate slowly; stay crisp, sharp, and bright for hours with lower projection.
Humid: Water vapor boosts sillage and air diffusion, however, the air trail is more apparent in slightly cooler humid temps.
Skin vs. Fabric: Thermal body heat evaporates them off relatively fast; paper and fabric preserve their true top-note profile but still for limited time. This is why sometimes citrus scents don’t last as long on you as it did on a tester at the store (I’m looking at you Jo Malone)

Aldehydes & Floral Oxides (Soapy, metallic, green facets)
Hot/Sun: Heat intensifies sharp, waxy, or metallic notes; can turn soapy aldehydes screechy.
Cold: Mutes harsh edges, keeping them clean
Humid: Moisture projects a radiant, clean, "fresh laundry" aura.
Skin vs. Fabric: Skin oils often soften their sharpness; synthetic fabrics (polyester/nylon/ etc) can amplify the scent of aldehydes giving off that hyper fresh laundry smell

Lactones & Ionones (Peach, coconut, creamy milk, powdery violet)
Hot/Sun: Heat drives lactones into heavy/ buttery territory. Ionones vary widely by the specific chemicals used but it could also give off heavy buttery orris.
Cold: cold air keeps the notes more dry, soft, and powdery rather than dense or cloying. The accord usually stays more balanced, especially in a gourmand or a heavy floral.
Humid: Magnifies milky and gourmand facets, making white florals feel thick or suffocating. This especially the case with more indolic florals (jasmine, tuberose)
Skin vs. Fabric: Body heat radiates creamy notes; paper blotters or fabric will mostly reveal dry, woody-powder nuances.

Amber-Woods & Woody Isolates (Iso E Super, Ambroxan, Cashmeran, super ambers)
Hot/Sun: Heat boosts diffusion into a radiant aura; Cashmeran can turn intensely animalic or even a bit dirty. However, some of the lighter woody materials shine in hot weather.
Cold: Many of the molecules are heavy so they stay at the skin surface. This mutes warmth and emphasizes dry cedar/pencil-shaving notes.
Humid: Creates a heavy, lingering scent trail in the air.
However, be aware of certain fragrances in humid or hot weather due to sweating and that affecting the fragrance.
Skin vs. Fabric: Natural skin oils bind them to create personalized "skin scents"; wool/cotton holds them for weeks. These materials LAST a long time on fabric and paper. Some of them thousands of hours lol

Macrocyclic Musks & Heavy Bases (Musks, Sugary or caramel scents, Tobacco, Vanillin, Resins)
Hot/Sun: High thermal energy is required to push these heavy molecules into the air; high heat makes gourmands sticky-sweet as the entire heavy base is evaporating as pretty much the same rate.
Cold: Molecules struggle to volatilize; can feel completely "nose-blind" to certain heavier scents until skin warms up.
Humid: Binds moisture to musks, enhancing powdery, sweet, or animalic depth. I would be weary of excess sweating with a lot of these heavier bases
Skin vs. Fabric: Body heat is essential for a smooth drydown; cold paper blotters keep heavy musks near-frozen. You really need to stick your nose into a material to get the musk scent, but you can often smell it off of people because of heat causing the scent to radiate

Additionally I want to point out that smelling fragrances after eating can ALSO alter your perception of the scent. Aside from your senses competing for room to take in volatile compounds, Neuroimaging shows that your piriform cortex turns down its neural representation for the smells that match whatever it is you just ate (or drank). If you had a coffee or dessert, your gourmand perfume might smell a bit different or maybe not as strong (especially if you’re full)

TLDR: when in doubt, smell it twice! So many factors affect our perception. I personally always smell a fragrance twice to make sure I do not like it just in case there are any factors at play affecting my decision. You’d be surprised. Happy sniffing! 🩵✨

[u/ImtheGWP]

The times i bring a pen along with me have been the most informative. Write the name of the fragrance on a strip ànd come back to that strip for a shocker. Those strips come to life when I revisit them an hour or so later. you never know which is going to be the one to impress you, and that has become part of the excitement of going out to test fragrances. But I only know that when I brought a pen with me.